lang: replace stack-based parser with a recursive parser

lang/parse/block.c

@@ -0,0 +1,103 @@
+#include "ctx.h"
+
+#include <ivy/lang/ast.h>
+
+static bool parse_block_params(
+	struct ivy_parser *parser, struct ivy_ast_block_node *block)
+{
+	while (1) {
+		if (parse_symbol(parser, IVY_SYM_PIPE)) {
+			break;
+		}
+
+		if (!parse_symbol(parser, IVY_SYM_COLON)) {
+			parse_trace(
+				parser,
+				"expected `|`, or `:` followed by parameter "
+				"name");
+			return false;
+		}
+
+		struct ivy_token *ident = NULL;
+		if (!parse_word(parser, &ident)) {
+			parse_trace(
+				parser,
+				"expected parameter identifier after `:`");
+			return false;
+		}
+
+		struct ivy_ast_ident_node *ident_node = create_node(IVY_AST_IDENT);
+		ident_node->n_content = ident;
+		fx_queue_push_back(&block->n_arg, &ident_node->n_base.n_entry);
+	}
+
+	return true;
+}
+
+bool parse_block(struct ivy_parser *parser, struct ivy_ast_node **out)
+{
+	if (!parse_symbol(parser, IVY_SYM_LEFT_BRACKET)) {
+		parse_trace(parser, "expected `[` before block contents");
+		return false;
+	}
+
+	struct ivy_ast_block_node *block = create_node(IVY_AST_BLOCK);
+	if (!block) {
+		parser->p_status = IVY_ERR_NO_MEMORY;
+		return false;
+	}
+
+	bool result = true;
+
+	if (peek_symbol(parser, IVY_SYM_COLON)) {
+		result = parse_block_params(parser, block);
+	}
+
+	if (!result) {
+		parse_trace(parser, "invalid block parameter list");
+		return false;
+	}
+
+	bool prev_was_expr = false;
+
+	while (1) {
+		struct ivy_ast_node *child = NULL;
+		if (parse_linefeed(parser)) {
+			continue;
+		}
+
+		if (parse_symbol(parser, IVY_SYM_RIGHT_BRACKET)) {
+			break;
+		}
+
+		if (prev_was_expr) {
+			if (!parse_symbol(parser, IVY_SYM_DOT)) {
+				parse_trace(
+					parser,
+					"expected `.` after expression");
+				result = false;
+				break;
+			}
+
+			prev_was_expr = false;
+			continue;
+		}
+
+		if (peek_expr_start(parser)) {
+			result = parse_expr(parser, EXPR_PARSE_NORMAL, &child);
+			prev_was_expr = true;
+		} else {
+			parse_trace(parser, "expected `]` or expression");
+			result = false;
+		}
+
+		if (!result || !child) {
+			break;
+		}
+
+		fx_queue_push_back(&block->n_expr, &child->n_entry);
+	}
+
+	*out = generic_node(block);
+	return result;
+}